Furnace structure and method of protecting the same



F. CORDES 4 FURNACE STRUCTURE AND METHOD OF PROTECTING THE SAME Filed July 8, 2 Sheets-Sheet 2 yETNTOR To all whom it may concern:

Patented Sept. 1, 1925.

UNITED STATES? rnANKjcoBDEs, or rrr'rsnqiaen, r NNsY vAN IA.

FURNACE'STRUCTURE AND mnarrnoi) on PROTECTING THESAMI'JJ Application filed "July 8,

Be it known that: I, FRANK Connns, a citi-' zen of the-United'States, residing at Pittsburgh; Allegheny. County, Pennsylvania, have invented a new and useful Improvement. in Furnace Structures and Methods of Protecting-the Sameyof which the follow ing is'a full, clear, and exact description.

The present invention'relates broadly to furnace construction, and more particularly to furnace stacks and a method of protectin the'same. l V

:Atthe present time, considerable difficulty islexperienced with high temperature stacks,

due to the iburning'out" of the" refractory lin-' f I having a1flue=3 for conducting-the'hotgases and products of combustion to the stack- 4;

ing and "the *high temperature -to which the 'metallicprotecting 'shell is raised, whereby thereon, but the" temperature tends to de not only is-it impossible to maintain paint stroy the metal. 1 Both the painting and the repaireither of the lining or of the shell are not bnly 'dangerou's 'operations accom-- panied with considerable difiiculty, but they are exceedingly expensive. Furthermore,

the temperature conditions' to which the shell is subjected result in expansion and contractionthereof to-such an extent as to cause shearing of the rivets which hold the plates together.

The present invention'has for one of its objects'the constructionvof a stack-which is less affected by the gases leaving the furnace and which has a materially greater length of life. I

Another object of the present invention is to supply supplemental air to the gases leaving the furnace in such manner as to complete the combustionv thereof and to both cool the stack and form a protective =coating of carbon on the innerfwalls'thereof,

In the accompanying drawings, there is shown for purposes of illustration only a preferred embodiment of the present inven tion, it being'understood that the'drawings do not define the limits of my invention, as

changes may be made in the construction and operation disclos'e'dtherein, without departing from the spirit of the invention'or the scope of my broader claims.

In theidrawingsz 15'? Figure 1 is a vertical sectional view through a portion of a furnace illustrating a portion of the furnace hearth, the stack and the connecting flue;

Figure 2 is a vertical sectional view partly broken away and partly in elevation, il-

pointed outare encountered.

1924. seriar'm. 724,785.

lustrating 5a 5 .preferredform of stack con-.- struction;

Figure 3 is *arntransverse sectional view on1anrenlarged "scale-on the line III-.-III.'6O of Figure 2;and-. f r -"ifi Figure 4-is a view similar; to Figure '3, but t'ake'n onthecline IVE-IV of Figure-'2:

The 'presentinventionwis not restricted to use with a ifurnac'esof anyxparticular construction, :and it will be understood that the drawings merelyillust'rate more-'orless' diagrammatically one-type of furnace construction in. combination .with .the improved stack. :nIn Figure-1 of thefldrawings',sthere* is; illu'strated a portion ofothe furnace. :2'

continuously --issues rat the top of the stacke It will be-gap'parent thatxunder such icondi tions thestack, which-has'a limited' radiatr ing' surface, lSi SlllI)] 8Cted tO: SuCll 'extreme temperatures that the objections heretofore In accordance with the present invention, there may be provided openings '5, permit ting the passage of air into the flue 3, adjacent the furnace 2.: This air, which is drawn through these openings, not only assists in the completion of combustion, but also is preferably admitted in such-amounts as to have a decided cooling effect in the flue and form a protective film of cooling air between the hot gases and the lining of the arch. This materially reduces the destructive action of the hot gases on the lining and correspondingly increases the length of life thereof.

In the base of the stack 4L, there are also preferably provided arch-like openings 6, which are adapted to be filled to a greater or lesser extent by placing bricks therein to control the amount of air supplied. This air further tends to complete the combustion of any unconsumed furnace gases a'nd"- to assist in cooling the base of the stack. By completing the combustion of the gases before they enter the stack-proper,- the' temperature in the stack is reduced thereby lessening the tendency to burn out the stack lining 7 or burn off the paint from the shell 8. Another advantage of supplying air through the openings in the base of the stack, particularly in connection with coalnace carry over withutheln fine particlesof 5 carbon and the air "entering through the openings projects these particles on to the mner surface of the stack lining before they are completely burned, thereby forming 'aprotective coating for the portions of the peratures.

z-The stack itselfis-also preferably of spe- *-cial3constructi'on whereby the shell 8 is further protected. In accordance with one embodiment en the i invention, the construction may-comprise brackets 9, :adjacent the base oftheistackythe brackets-having lugs 10 for supporting-the I'IOVVGIL: end of .the shell 8. This zshell throughout the length of the stack ispreferably maintained inspaced relationi-to :the lining 7' .by projections 11, friomntheislining. 5 It will beunderstood by thoseiskilledtin the-art that this lining may comprise any suitable refractory body or material, .either ;in-the :form ofnbricks or blocks .or of more or less. solid construction formedrimsitu; =.-Irrespective of the pa-rticu- 7 lar i .methodof construction, there will be 1 providedfithe projections 11, preferably at certain definitegpoints, these projections in adjacent courses orarows being staggered, as clearly-showniin Figure 2,;to provide a tor.- "tuous: flow 1 path the'rebetjweene The 'l brackets-. arevformed with air admission openings 12, permittingthe passage of air into thespace'between the shell and the lining. Thiseair circulating between and around the lprojections'll, forms a protective film not onlytending to cool the outer surface of the lining and the inner surface of the shell, but also tending to prevent the eifective transmission of heat from the lining to the shell.

In actual operation, it has been found that a stack constructed as disclosed herein will, retain. an effective coating of paint thereon due to the much lower temperatures encountered.

The advantages of the present invention arise notonly from the method of supplying supplemental air for complete combustion of thehot gases, assisting in-Hcooling and forminma rotective coatim but also from the construction of the-stack itself, whereby the shell is protected from the temperature conditions obtaining within the stack.

I claim-z 161A furnace-comprising a stack and a flue connecting stacklining subjected to the highest temthe furnace with the stack,

furnace whereby to supply a film of cooling airbetween the hot furnace gases and-said top Wall, substantially as described.

3. A furnace comprising a stack and a fine connecting the furnace with the stack, said flue having an air admission opening therein-adjacent the furnace and said stack having an air admission opening therein adjacent the base thereof, substantially as described. I

4. A stack comprising a refractory lining having a plurality of spacedstaggered projections, and-a shell enclosing said lining and'held in spaced relatio-nthereto, by said projections, there being openings for the admission 'of air to the space between said shell and lining, substantially as described.

5. A stack comprising allining and a shell maintained in spaced relationthereto, said stack having openings adjacent the base thereof for the admission of air into the stack,- substantially as described.

6. A stack ;comprising a lining and a shell maintained in spaced relation, tl1ereto,

said stack having openings adjacent the base thereof for the admission of air into the stack, said openings being adjustable to vary the amount of air admitted. to the stack, substantially as described.

'7. A stack comprising a lining and a metal shell extending substantially the full height of the stack, and means for maintaining said shell in spaced relation to the lining, therebeing openings adjacent the lower end of the shell for the admission of air to the space between said shell and lining, substantially as described. 1

8. A stack comprising a lining and a shell held in spaced relation thereto, there being openings adjacent the lower end of Said shell for the admission of air to the space between said shell and lining, the construction being such that the air is compelled to ascend the space between the lining and the shell in a tortuous path, substantially as de- FRANK conDEs. 

